Methods::
Retinas from wt, RPE 65 -/-affected and treated dogs were analyzed.The treatment consisted in one single subretinal injection ofrAAV-mediated RPE65. The dog retinas were analyzed at 17 monthsof age in affected and treated animals. In the treated animals,the injection of rAAV was performed 5 months before the analysis.The retinas then processed for immunocytochemistry, and thedifferent cell types were examined using antibodies againstvarious molecular markers of the outer retina (M/Lopsin, S opsin,hCAR and rod opsin), inner retina (Goα or PKC, Calretinin, GABA,TH, BDNF) and glial cells (GFAP and vimentin). RPE65 labelingwas used as a marker to identify treated areas.

Results::
In affected retinas we found a decrease in the expression ofphotoreceptor and amacrine cell markers, increase in the expressionof glial markers, and changes in the synaptic processes of amacrineand bipolar cells. After treatment, we found a restoration inthe expression of the photoreceptor, glial and amacrine markers.However, 5 moths after treatment, the synaptic changes in theinner retina are still present.